from collections import defaultdict
import networkx as nx
H,W = map(int,input().split())
A = []
dic = defaultdict(list) 
for i in range(H):
    a = list(map(int,input().split()))
    for j in range(W):
        num = a[j]
        if num != 0:
            dic[num].append((i,j))
    A.append(a)
print(A)
print(dic)
key_list = list(dic.keys())
#頂点は0~H+W-1
S = H+W
T = H+W + 1
ans = 0
for num in key_list:
    G1 = nx.Graph()
    G1 = nx.DiGraph(G1)
    SX = set([])
    SY = set([])
    for x,y in dic[num]:
        SX.add(x)
        SY.add(y)
        G1.add_edge(x,y+H,capacity=1)
    print(SX,SY)
    for x in SX:
        G1.add_edge(S,x,capacity=1)
    for y in SY:
        G1.add_edge(y+H,T,capacity=1)
    flow_value, flows = nx.maximum_flow(G1,S,T)
    #print(num,flow_value,flows)
    ans += flow_value
print(ans)